Lawyers for James “Whitey” Bulger said Monday that he is not claiming a blanket “license to kill” by asserting that a former US Justice Department ­official granted him immunity from prosecution for crimes includ­ing murder.

Instead, Bulger’s lawyers said in court filings, he asserts that an agreement he had with the late Jeremiah O’Sullivan, a former federal prosecutor in Boston, only barred federal author­ities in Massachusetts from charging him criminally as long as he kept his end of the bargain.

“The defendant did not possess a license to kill, but rather an agreement with the [Depart­ment] of Justice,” ­defense lawyers wrote.

Bulger’s lawyers have not said what he agreed to do in ­exchange for federal immunity. He denies being an informant, despite evidence from prior court proceedings that he provided information to the FBI for years.

Federal prosecutors contend that there is no evidence that O’Sullivan offered Bulger immu­nity and that O’Sullivan lacked authority to enter into such an agreement.

In the court filings Monday, defense lawyers asked US District Court Judge Denise J. Casper, to allow Bulger to present his immunity defense at ­trial, a request that her predecessor denied last month.